The magnetics are made up of both a 1 to 1 isolation xformer and a cm choke. I
just stared at a schematic and I don't know if its an error, a single part or
generic, but for this one part the common mode choke was on the cable side for
the TX lines and on the IC side for the RX lines. I have never noticed that
before. I'll be looking at some other parts now that you have my interest
piqued.
Gary
From: Muhammad Sagarwala [mailto:msa...@force10networks.com]
Sent: Monday, February 03, 2003 9:00 AM
To: emc-p...@majordomo.ieee.org
Subject: rj45 with integrated magnetics..
Here is a question for you Gurus..
I was looked at a few different rj45 with integrated magnetics. While all of
them were different in some respect, I found two major categories - one with
common mode choke on the chip (IC) side while others with common mode choke on
the cable side. My question would be "why would one want to use a connector
with common mode choke on the chip side vs connector with common mode choke on
the cable side??? I wanted to know specific scenario where a person would
prefer one over the other."
Here I would like to add that most of the problems I have seen in my short
career are due to common mode noise making its way to the cable.
Also, I would appreciate if someone could point me to a document where I could
find rules/factors to consider while selecting a jack with integrated
magnetics .
Muhammad
